Ripper boots are typically used where extremely hard rock or compacted soil is encountered and is required to be penetrated and ripped in an attempt to locate and extract precious stones such as opal. The ripper boot includes a carrier which is typically secured to a bulldozer tyne and a ripping tooth section secured to the nose of the carrier to rip through rock, typically to a depth of approximately 300 mm at a time. In the case of opal mining, the loosened rock is then pushed away, while spotters check for signs of opal. The ripping tooth can also be replaceable. The present inventor has identified some problems with such conventional ripper boots.
Firstly, some replaceable ripping tooth sections are secured to the boot in a rotatable manner. The problem with having a rotatable ripping tooth is that during operation, ground up rock is able to enter into the area between the shaft of the ripping tooth and the ripper boot body. This causes considerable wear and tear when the shaft rotates which may eventually lead to metal fatigue and fracture under extreme loads. A further problem is that the ripping tooth tends to move and chatter during operation which is also undesirable. Further still, where clay fines and other similar material build up in the area surrounding the ripping tooth shaft, the tooth becomes almost impossible to remove. Existing ripper boots having rotatable teeth are also expensive to manufacture, and their use is limited to only a small range of applications.
The present inventor has further discovered that the “angle of attack” is extremely important in ripping operations, that is, the angle at which the ripping boot rips through the ground. In conventional ripping operations, the angle of attack is typically governed by the angle at which the end of the bulldozer tyne extends because it is the tyne that carries the ripper boot. The position of the bulldozer tyne is adjustable, however, its movement is restricted and often a desired angle of attack is not attainable.
When the tooth is ripping at too steep an angle, that is, when the angle between the longitudinal axis of the ripping tooth and the ground surface is too great, the ripper boot will begin to chatter which may result in increased wear and tear on the ripping tooth, metal fatigue and eventual fracture in the ripping tooth. In such circumstances, the load on the bulldozer is also increased which leads to increased fuel consumption. The nose of the ripping tooth tip may also drag when the angle is too steep, and the ripping tooth is prone to being ripped out. In general, where the angle of attack is not correct, the required cleaving effect of the boot is reduced. In fact, it has been found that very small variations in ripping tooth angle can have major effects on the effectiveness of the ripping operation.
It is therefore an object of the present invention to overcome at least some of the aforementioned problems or to provide the public with a useful alternative.